During the construction of a building roof, it is very common for roof trusses to be used. A roof truss is typically made of timber (although metal roof trusses are also known) and comprises a number of lengths of timber or metal which are attached together to form the truss. A roof truss can be made to any suitable length and this will typically be between 4-10 meters. The roof truss can also be made to any suitable height and this can be between 1-4 meters. These roof trusses are placed in a side-by-side and spaced relationship relative to each other. Battens are then attached to the trusses and cross braces are used to provide a rigid structure onto which tiles or metal sheets or other types of roof covering members can be attached. The spacing between roof trusses can vary depending on the type of roof covering that will be used, the wind loading, the size of the truss and the like. The spacing between roof trusses will typically be between 0.5-2 meters. Thus, it can be seen that a typical building will have a multiplicity of roof trusses and a typical domestic dwelling can have anywhere between 10-100 roof trusses and commercial dwellings can have even more.
It is important to ensure that the roof trusses are spaced apart by the correct distance in order to comply with local government requirements, wind loading requirements, the weight of roof tiles and the like. If the roof trusses are spaced too close together, too many trusses will be used which will increase the building cost and if the roof trusses are spaced too far apart, the roof strength may be compromised.
The design of the roof truss is such that when the roof truss is placed in an upright manner on top of the building, the truss will tip over unless it is supported prior to attachment of the battens and the cross bracing. Conventionally, the required number of roof trusses are lifted on top of the roof by a crane. A carpenter can then lift up one roof truss to the vertical position and will nail one end of a small measured wooden length to the roof truss. The next roof truss is then lifted into the vertical position and the other end of the length is nailed to the roof truss to hold the two roof trusses together. This procedure is then repeated with any required number of wooden lengths until all the trusses are in the vertical position. Then the battens are nailed or otherwise attached to the trusses and cross braces are attached to hold everything in position.
There are many disadvantages with the conventional method to hold the roof battens in position during the preliminary stages. One disadvantage is that the small wooden lengths are quite thin and are usually nailed by a single nail into each truss to hold the trusses together temporarily. For larger trusses, this attachment is quite insecure. Should a truss become dislodged, it can tip against an adjacent truss and it is possible for all the trusses to collapse in a domino-type fashion. This can cause injury to the carpenter on the roof. This person could accidentally push against a truss and dislodge the truss. Also, the carpenter needs to precut the required number of lengths of wood which will form the spacers and the temporary attachment between the trusses to ensure that the trusses are held apart by the necessary distance. As mentioned previously, the spacing between trusses can vary depending on the size of the truss and other factors. Therefore, the carpenter generally needs to precut the wooden lengths on-site depending on the type of truss that is to be used. This is time-consuming and generally unsatisfactory.
Another disadvantage, and particularly a safety disadvantage is that the above conventional system results in a number of individual (typically wooden) lengths being nailed or otherwise temporarily attached to the truss. With this system, it is possible to break or accidentally removed one length. This can result in collapse of the truss. Therefore, there would be an advantage if a system could be developed that could prevent a temporary brace from being accidentally removed in midsection that can lead to a serious accident.
Various attempts have been made to develop tools for roof trusses and the like. Most of these however, are designed to space frame members apart and not really to temporarily hold or brace two frame members together. Some of these tools are length adjustable. Many of these suffer from two main disadvantages. The first disadvantage is that the tool does not really clampingly engage with a particular truss and is therefore more easy to accidentally remove. For instance, U.S. Pat. No. 5,490,334 describes a tool which can hold a stud/rafter, but this is done using a wedging action, and not a clamping action. Thus, it is possible to knock out the tool. A second main disadvantage is that the tool really functions only to hold two trusses in position and there is no real mechanism to enable a large number of trusses to be temporarily braced in a safe and relatively simple manner. As an example, a truss holding tool is described in U.S. Pat. No. 4,704,209. This tool is designed only to hold a pair of trusses, and therefore if it is necessary to hold more than a pair of trusses, it is necessary to use a number of these tools. However, each tool works independently from each other tool which means that if one tool is inadvertently removed, the trusses can collapse. Therefore, there would be an advantage if it were possible to develop a clamping assembly where a plurality of clamping tools could be preferably held to each other, as opposed to separately, to define a “string” or “chain” of clamping tools. This would make it difficult to inadvertently remove an intermediate tool that can cause collapse of the trusses. To explain, it is much safer to remove the tools from one end truss and working along each other truss as opposed to removing the tools from a position intermediate the ends.
Therefore, there would be an advantage if there was a different way by which trusses could be held in place during the preliminary stages of the erection of the trusses and which would be safer with less chance of the trusses becoming dislodged, and possibly which would enable the various spacing between the trusses to be accommodated.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.